Spring motor



Ju y 3, 1935 N. E. SINDLINGER 3,l94,344

SPRING MOTOR Filed May 4, 1964 2 Sheets-Sheet 1 FIG. 3

L l l ZOB IS INVENTOR. s NORMAN E. SINDLINGER BY FI G 3 %i ATTORNEYS andSecured to drum 12 at 15.

United States Parent O Deiaware Filed May 4, 1364, Ser. No, %4,626 '16Ciaims. (Ci. ISS-%9) This invention relates to a motor of the springtype and more particularly relates to such a motor which can exert aplurality of substantially different and substantially constant forces.

In many applications it is desirab'le to have a spring motor which canproduce a number of di erent forces which are relatively constant.Further, in certain fields such as in the field of orthopedic tensioningit is highly desirable to be able to change these forces withoutmovement of the output means associated with the motor.

*It `is therefore a primary object of this invention to provide avariable force spring motor which can produce a plurality of differentsub'stantially constant forces which can be Varied without movement ofthe output means associated with the motor.

Relative to the prior art, tightly coiled noncumulative force ribbonsprings are well known and are in wide commercial use. Such springs aredisclosed in United States 'Patents No. 2,609,191 and No. 2,609,i92,both issued on September 2, 1952. Further, it is known to employ suchsprings to make an "A motor by coiling such a spring directly onto apair of spaced drums as disciosed in FIGURE 11 of Patent No. 2,647,74-3,issued August 4, 1953. Sueh a spring may also be used to make a B motorby coiling it directly on one drum and reverse wind-ing -it onto aspaced second drum (see Patent No. 2,063,799, issued November 8, 1936).motors as used commercially generally have a zero or very small gradientand are not capable of producing abrupt and substantial changes -in theoutput force when under load and without movement of the associatedoutput means. It is therefore unexpected that 'such a result can beachieved with this invention.

The invention and its objeets will be further clarified on reading thefollowing description in conjunction with the drawings in which:

*FIGURE 1 is a side elevation of a spring motor ernbodying theinvention;

FIGURE 2 is a plan View of the spring motor of FIG- URE i;

FEGURE 3 is a vertical section partially broken away taken on the planeindicated by the line 3-3 in FIG- URE 1;

FGURE 4 is a plan View partially broken away of an extended portion ofthe 'spring of the motor of FIGURE 1;

FIGURE 5 is a graph of the torque of a typical motor of the invention;

FEGURE 6 -is a diagrammatic plan View of an alternative embodiment ofthe invention; p

FIGURE 7 is a diagrammatic plan view of a second alternative embodimentof the invention; and

FIGURE 8 is a plan view partially broken away of a spring for a motor ofthe invention shown in a fuily extended condition.

Referring to FIGURES 1 and 2, a spring motor 2 in accordance with theinvention has a 'base 4. A shaft 6 is rotatably mounted in supportmembers 8 and ll@ which are fixedly 'Secured to base 4. A stepped drum12 is fixedly Secured to shaft 6.

The outer end of a tightly coiled non-cumulative ribbon spring M isreversely wound onto out-put drum 12 As in the case 'of an ordi- Suchnary B motor, spring 14 tends to coil tightly onto a storage drum 16which is rnounted for free rotation about a shaft 13 which is Secured toU frame Zi). Frarne 2@ is rotatably mounted on shaft 6 by bearingsindicated at ZiA and Zt'iB and is provided with a handle 22.

Spring 14 ditfers from the conventional tightly coiled non-cumulativeforce ribbon spring employed With a B motor in that it has a pluralityof portions having substantially different widths indicated at 14a, 145,Mc, l id and Me with relativeiy short transition portions therebetweenas illust-rated at Me' in FIGURE 4. By Way of specific illustration,each of the portions having a dierent width may be of -a length to placeapproxmately three turns on storage dru-in 16 with the transitionportions each being of a length equal to about %i of a turn. Thesefigures are given merely by way of illustration and obviously may bewidely varied. The force exerted by the spring M Will vary directly Withchanges of width.

The torque exerted on shaft 6 for a typical motor is illustrated inFIGUR 5 with the torque in pound inches being plotted against the numberof turns drum 17; has made in winding spring 14 onto drum 12. in FIGURE5 .the portions of the plotted line corresponding to the portions ofspring M producng the line have been labeled with the number applied tothat portion of the spring. Fer purposes of iilustration, it will beassumed .that portion :t ia of spring id is /2 of an inch wide and willexert a torque of 2 pound inches; and that each succeeding portion isincreased in Width by of an inch. As practically shown in FI URE S, thiswill result in a series of force variations ranging from a for-ce of twopound inches when portion I io is in play and a force of four poundinches When portion Me is in play. As is well known, the torque isdeveloped by virtue of two concu'rently working factors, mainly thestraightening of spring 14- as it is unwound from storage drum 16 andthe reverse bending of spring M as it is wound onto drum 12. Thus when atransition portion such as MA' commences to unwind from storage drum 16,i.e. is being straightened adjaoent storage drum 16, an increase intorque results. This is illustrated -by the portion Ll of the plottedline. As the transition portion MA' moves between drums 12 'and 16 in a-straightened condition, the torqne exerted will remain substantiallyconstant .as indicate& by the portion LE of the plotted line. Then asthe portion l iA' is being reversely bent to be coi-led onto drum 12,the torque Will rapidly increase as indicated by the portion L3 of theplotted line until it has all been wound onto drum 12 and the -onlyacting portion of spring 14 is portion Mb. At this stage, a higherconstant torque will have been rea-ched as indicated at MB. This actionis repeated as the transition is made from each portion of the spring 14to the next wider portion. It Will be apparent that the reverse effectis achieved when going from each portion of spring 14 to the nextnarrower portion.

Referring now to FIGURES 1 and 2, a ratchet wheel 26 fixedly Secured toU frame 2% is engaged by a pawl 23 pivotally Secured as indicated at 3@and biased against ratchet wheel 28 by an extension coil spring 32. PaWl28 has a handle portion indicated at 34.

Flange 33 of tube i@ is fixedly Secured to frame Zi) and carries a setscrew 42; which engages a slot 4 4 in a calibrated tube 46. Tube 46threadably engages shat 6 as indicate& at 43. p

As'seen in FIGURE 2, a drum 52 has a cable 54 coiled thereon and isfixedly Secured to shaft 6. Cable 54 has a looped end 55 secured by aclamp 58 which engages braclet &ti secured to base 4. Bracket 6@ has anopening 62 to accomnodate cable 54, but too small to accept clarnp 53. i

'brated tube 546. wound or unwound with respectto dru'm12 there willrhe`&3 Opei'aticm With the parts in the positions shownrii FIGURES 1 and 2the extension of cable 54- will result in a t-orque of 2 pound inches'during the rotati-on of drum 12 forapproxij .rnately 2%. turns assumingthe torque c-haraoteristics to -be .as shown in FIGURE 5. t Thus for ashort stroke of cable 54 a substantially uniform `tensioning force `isachieved. Assuming that cable 54 'is extended a very short distanceto'just clearclamp 58 from'bracket 60, the

'tensioning force exerted by the motor can be changed without movementof 'cable 54 by moving the handle bodiment of FIGURE' i.

Similarly when cahle'm'is being r wound'onto drum:76`,`sprng 14j`wi11{be unwound from" porti-on '34 of pawl 28 downwardly to release the pawlfrom' ratchet wheel 26 and simultaneously rotating the frame byhandlezzclockwise as viewed in FIGURE 1 t-o wind spring 14 onto drum12 until,for example; ?the leading ?part of portion 14-!) commences to Wind ontodrumll This Will result inincreasing the tensioning force, to the nexthigher force level *at which point again a substantially constant forcewill'he exerted for a short stroke of cable' 54. i

' The force being exerted Will be `indicated bythe 'cali- Irrespectiveof whether the spring is relative aXial movement of tube 46 with respectto tube it? since in either case there will be relative rotation betweenspring employed will show the force being exerted i Alternativeembodment The windin'g and unwinding of the tightly coiled non--cumulative orce'ribbon spring with-respect to the output' drum-12 ontost0ragedrum16'.; i

An alternativelembodiment is shown' inCEIGURE 7 in which the;output'shaft ?hand associated drum and cable elements of FIGURE'Gareemployed and'given i identical .numb ers.- Inl this embodiment,shaftl71 is; fixedly, securedz to a lever' 13@ on-*which js rotatablymounted' a gear lzgwhich engages -a- ;ring,gear134' mounted :forrotation 'about a shaft`136; .A gear-138 fixedly Secured to .shaft `136,also 'engages gear132.j Ini tegral with ring gear134 isa gear l itlwhich'engages gear l tz fixedlysecured to-a-shaft144 rotatably mounted,t insupportmembrsl i and 148.' *Shaft l tt 'is fixedly secured to acrank 159.: 'A pin 152 ,whichis adaptedto.

enter an opening 154 in crank-150 andan opening 156 i in bracket 153 :isemployed to secure crank 150111 a fixed position. r For 'fineradjustrnent a ratchet-may beemi ployed. An output drum 12,' atightlycoiledtnon-'cumulative force ribbon spring14 and a storage drum 16identical i with those employedinthe' em hodiment of FlGUREil areg;

tube 46 and shaft 6. Thus tube 46 being calibrated to the drumwithoutrotating of .the output shaft can be accome plished 'in a 'numberof difierentways. An alternative embodiment is shown in FIGURE 6. Here aspring 'motor has an output shaft 71 mounted for rotationin supportmembers 72,and '74, a drum 76 is fixedly Secured to shaf-t'71andrcarries a cable 78`whch has a looped end :80 securedby a clamp 82which is adapted to engage a bracket-84 having an opening 86 throughwhich cable 78 passes. t

A 'gear 99 fixedly 'Secured to shaft 71 engages a' gear 4 V 92 fixedlySecured to a shaft'94 which in turn is rotatahly 'm-ounted in lever 96.'Lever 96 is fixedly' -se-cured to a shaft 98 mounted tor rotation insupport members 100 e and 5192.. A crank 104 'is xedly -secured toshatt-93 which is coaxial with shaft 71. A stop pinflo is adapted to.pass through'an opening in crank 104 and an opening in bracket 112 tolock crank 194 in a predetermined position. 'For finer vadju stment, ara-tchet may 'be employed( An output drum 12, a tightly coiled non-cumu-Drum 12 is fixedly Secured to shaft %and drum 16 is mounted forrotationon a shatt 114 which is secured to support members 116-'and `118.

, Operqt'on In this embodiment, when crank 104 isreleased for`movementby-withdrawa1 of pin 106 from' bracket 112,;

crank 10.4 can be'employed to rotate shaft 98 and lever ;196 to causethe rotation of shaft 94 bodily about the axisof shaft 71 which causesthe rotation of shaft 94 about its axi incidentto the interaction'ofgear 92 with latve force ribbon spring 14 and a storagedrum 16 are v allidentical Withthe similarly-numbered elementsof the v `embodiment of FIGURE 1.

stationarygear 96. bIn this manner spring 14 can be- `wouncl. up ontoortunwound-from drum 12 to `varfithe output force-without any movement' ofoutputshaft 71 or cable 78 when cable 78 is under load. When-crank ,104is held *stationary by pin 106 being engaged with bracket;"112, the'extension of cable '78 will cause the winding 'up of 'spring 14 ontodrum 12 by vrtue of the;

stant as was thoroughly discussed with respect to the em- ,-rotation ofshaft 71, gear 90, gear 92 and shaft 94. Withv `in a limitezi ra'nge thetension -force exerted willbe conused( Outputdrum' :12 is fixedlySecured torshaft l which' is mounted tor rotation `in support'members162" and 154. Storagedrum'l is ;mounted for' rotationz on i a shah-166which in turnis Secured to support membersj In operationof thisembodiment, the removal'of pin':

152 permits the rotation of crank lsti'torotate shaft144 'v and gears142 andl ttjtothereby r-otatering gear-134. Output shaft71 and armltiremainjstationary, therotam tion of ring gear 134 causes the rotationof gear 132 about g its ax-is and the consequent rotation of gear 13.8tand shaft 135 to cause thelrotation of d'rum12 to' windior unwind; 1'spring 14` on drum 12 to changcthe outputforce to the e desired force;;When leverrlsfiis 'held from rnovement by' j pin 152 in engagement withbracketrls; 'theextension of cable78 'and the consequentrotation ofshaft :711and t arm 1130 causes gear 132 :to be` carried'fabouti bodilyi within the statio'nary 'ring gear' 134 'which' in turn causs gear'132to rotate aboutits axis* and rotate gear ls and r haft" 136 tounwindribbon ,42 from'storage/drum16* V occurs' inthe winding ontooutput drum :12. The; reverse up of cable' 78 on drum 76. i 1

Where a substantial variation in yet a gradient canzbe-tolerated, aconstant var-iation in' forces is` desi ned and K i the width of thespring can be; employed as illustratediu the. spring shown totallyextended in l I G URE8.` Springs of this type are known' to 'the art,tbein'g ;disclosed in Patent No. 2,6G9,193, issued September- 241952 Simi-vlarly other motor formsemploying tightlylcoiled 'nonlieu of the,`reverse? wind-lng employ d j these embod ments i between the 'output andstoragefdrums.

It will ,he understand that'theabove described embodi ments are by way'of'illustration only andare not intende d to be limitng.

What is claimediszw v u i 1. In=combinati ona springmotor comprising .an'out-4 put drum, a storage drumg said drums having spaced substantiallyParallel aXS and a tightly .coiled .non-cumulative force .ribbon springconnecting saidclrums andtendv ingtouncoil 'fromtheohtpu-tdrum:andtocoil onto the.: i

storage drum, said spring havingfla pluralitygof portio'nsoftdfferentwidths, 'output meanszconnected tothe out V i Furthe', theintermediate stagetorque; L2 of FIGURE. -5 can b'e increased'if idesired?to have intermediateflforcen steps of greater extent `bydecreasing'thelength oftthe.- transition portionsofthe spring orinreasingthe distance V &194 344 put drum and means to transfer portionsof the spring from one of said drums to the other of said drums Withoutmovement of the output means.

2. The combination of claim 1 in which said spring has a plurality ofportions of substantial length each having a substantially uniform widthand with adjacent such portions having substantially difierent widths.

3. The combination of claim 1 in which the spring for -a substantialportion of its length is tapered from one Width to a substantiallygreater width.

4. The combination of claim l in which the transfer means comprisesmeans to rotate one of said drums about the axis of the other drum.

5. The combination of claim 1 in which the transfer means comprisesmeans to rotate the output drum independently of the output means.

6. The combination of claim 1 in which the output means includes a shaftand a gear Secured to the shaft and is connected to the output drumthrough a gear connected to the drum and the transfer means comprisesmeans to rotate the output drum about the axis of the output shaft.

7. The combination of claim 1 in which the output means and the transfermeans include dilferential gear means to provide for the rotation of theoutput drum independent of movement of the output means.

8. The combination of claim 1 in which the output means includes a shaftand is connected to the output drum through an arm Secured to the outputshaft, a planet gear Secured to the arm, a ring gear engaging the planetgear and a gear engaging the planet gear and connected to the outputdrum and the transfer means comprises a gear integral and coaxial Withthe ring gear and a driving gear engaging the gear integral With thering gear and means to control the positions of said driving gear.

9. The combination ot claim 4 in which said spring has a plurality ofportions of substantial length each having a substantially uniforrnwidth and with adjacent such portions having substantially differentwidths.

10. The combination of claim 4 in which the spring for a substantialportion of its length is tapered from one width to a substan-tiallygreater width.

11. The combination of claim 5 in which said spring has a plurality ofportions of substantial length each having a substantially uniform widthand with adjacent such portions having substantially different widths.

12. The combination of claim 5 in which the spring for a substantialportion of its length is tapered from one Width to a substantiallygreater Width.

13. The combination of claim 6 in which said spring has a plurality ofportions of substantial length each having a substantially uniform widthand With adjacent such portions having substantially different widths.

14. The combnation of claim 6 in which the spring for a substantialportion of its length is tapered from one width to a substantiallygreater width.

15. The combination of claim 8 in which said spring has a plurality ofportions of substantial length each having a substantially uniform widthand with adjacent such portions having substantially different widths.

16. The combination of claim 8 in which the spring for a substantialportion of its length is tapered from one Width to a substantiallygreater width.

No references cited.

JULIUS E. WEST, Primary Exam'ner.

1. IN COMBINATION A SPRING MOTOR COMPRISING AN OUTPUT DRUM, A STORAGEDRU, SAID DRUMS HAVING SPACED SUBSTANTIALLY PARALLEL AXES, AND A TIGHTLYCOILED NON-CUMULATIVE FORCE RIBBON SPRING CONNECTING SAID DRUMS ANDTENDING TO UNCOIL FROM THE OUTPUT DRUM AND TO COIL ONTO THE STORAGEDRUM, SAID SPRING HAVING A PLURALITY OF PORTIONS OF DIFFERENT WIDTHS,OUTPUT MEANS CONNECTED TO THE OUT-